Forty-five prisoners housed in Virginia's only super-maximum security prison began a hunger strike on Tuesday, demanding an end to what they say are the prison's poor living conditions and inhumane practice of segregation via solitary confinement.

The inmates resorted to the strike after the warden of Red Onion State Prison refused to address complaints about the institution's quality of life and use of prolonged solitary confinement, which the strikers describe as torture.

In March, Virginia state officials said they would implement reforms in the prison as part of Gov. Robert F. McDonnell's four-year plan to help prisoners re-enter society. But after months of inaction, the prisoners say the changes are not coming fast enough for the nearly 500 inmates at Red Onion who spend 23 hours a day locked in a cell.

A coalition of groups, under the name Solidarity with Virginia Prison Hunger Strikers, sent a letter with to McDonnell, in addition to Virginia U.S. Sens. James Webb and Mark R. Warner, both Democrats, on Tuesday listing 10 demands by the striking inmates.

Many of the demands center around basic quality-of-life requests, such as improved access to nutritious foods like fruits and vegetables and adequate medical care. The prisoners are also requesting sanitary improvements -- for instance, as of now they claim they are forced to clean their prison cells, including the inside of their toilets, with a single sponge and our bare hands, something they say promotes the spread of disease-carrying bacteria.

They are also demanding an end to indefinite solitary confinement, through the implementation of an administrative system where prisoners can earn the right to be released from segregation.

25,000 In U.S. In Solitary Confinement

Although it is difficult to determine just how many prisoners are held in solitary confinement in the U.S., a widely accepted 2005 study from the National Criminal Justice Reference Center found that about 25,000 men and women were being segregated in supermax prisons across the U.S. However, the figure is likely much higher, since the report did not account for the tens of thousands of inmates held in Secure Housing Units, Restricted Housing Units and other isolation cells in prisons and jails that are not supermax facilities.

In a statement to The Washington Post, Red Onion officials insisted their use of prisoner segregation is not equivalent to torture.

Red Onion has always operated constitutionally and protected the Eighth Amendment rights of offenders, and has been nationally accredited by the American Correctional Association, the statement said. The [Department of Corrections] is continually looking at ways to improve its operations and to enhance management of offenders by applying science as it evolves in the field of corrections.

In March, three members of the Virginia General Assembly asked the U.S. Department of Justice to investigate the state's use of solitary confinement, which state Del. Patrick A. Hope described as psychological torture.

The effects of extended isolation have been shown to have enormous consequences on prisoners' mental health, a particularly disturbing detail since many of the inmates housed in solitary confinement are already mentally ill. A 2010 study published in the Journal of the American Academy of Psychiatry and the Law found that physicians working in U.S. prison facilities are facing unprecedented ethical challenges arising from dual loyalties to mentally ill patients -- whose symptoms are typically exacerbated by segregation -- and their employers.

Solitary confinement is recognized as difficult to withstand;  indeed, psychological stressors such as isolation can be as clinically distressing as physical torture, states the study. Nevertheless, U.S. prison officials have increasingly embraced a variant of solitary confinement to punish and control difficult or dangerous prisoners.

Prisoners held in solitary confinement are typically kept behind a solid steel door for 23 hours a day, with infrequent access to showers, exercise or any form of human companionship. The practice can result in a range of mental health impairments such as visual or auditory hallucinations, insomnia, paranoia, distortions of time and perception and post-traumatic stress disorder.

The Virginia hunger strike comes only months after as many 4,250 California state prisoners skipped meals as part of a three-week hunger protest of the overuse of solitary confinement. While the strike was the subject of national media attention, the state ultimately did not meet any of the inmates' demands.